(() => {
    console.log("哈哈哈哈");

    interface Person {
        readonly name: string,//只读
        age: number,//必须有
        sex: string,//必须有
        hobby?: string//可有可无
    }
    const person: Person = {
        name: "张三",
        age: 20,
        sex: "男"
    }
    person.hobby = "唱歌"
    // person.name = "李四"
    console.log(person);

})()